Photoelectric sound apparatus



Filed April 23, 1934 2 Sheets-Sheet 1 May 4, 1937.

PHOTOELECTR IC SOUND APPARATUS H. G. WEISS Filed April 25, 1934 2 Sheets-Sheet 2 lngy G M455 Patented May 4, 1937 UNITED STATES PATENT OFFICE 10 Claims.

This invention relates to photo-electric sound apparatus such as forms part of various known means for recording and reproducing sound recordings by the use of linear phonogram carriers, for example film strips and other forms of tapes or ribbons.

An object of the invention is to provide a novel,

! simple, and inexpensive form of means for exciting a photo-electric cell in connection with sound recording or reproducing apparatus.

Another object of the invention is to provide an exciting means of the above character wherein is obviated the use of expensive lenses and lamps.

Another object of the invention is to provide means of the character stated, which, after an initial adjustment, requires no periodic adjustments during use, this feature being characteristic and rendering the device distinctively different from devices heretofore known and used for the same purpose.

A further object of the invention is to provide a device of the character stated, which may readily be installed on existing motion picture apparatus.

The foregoing and other objects are attained by the means described herein and disclosed in the accompanying drawings, in which:

Fig. 1 is a fragmental elevational view of a motion picture projecting machine embodying the device of the invention enclosed within a casing.

Fig. 2 is a front elevational view of the device of invention, the casing being removed.

Fig. 3 is a side elevational view of the Fig. 2 device.

Fig. 4 is a top plan view of the device.

Fig. 5 is a cross-sectional view taken on line 55 of Fig. 3.

Fig. 6 is a cross-sectional view taken on line 6-6 of Fig. 2.

It is known to be common practice to equip motion picture projecting machines with sound reproducing apparatus comprising a photo-electric cell and associated means for setting up electrical currents corresponding, in frequency vari- 5 ations, with light acoustically modulated by reason of its passage through the sound recording portion of a translucent film. The sound area of the film ordinarily is produced by photographic recordation, and the light rays to be modulated emanate from a low-voltage high-amperage exciter lamp positioned to project a narrow beam, in the form of a slit, through the film record and onto the anode of a photo-electric cell, to produce varying electrical currents which are then transformed into sound waves by the use of means including a loud speaker or sound amplifier.

Heretofore, the means for condensing the exciter lamp rays and projecting them as a narrow slit upon the film, required the use of expensive lenses and complicated expensive means for adjusting the size of the slit as the filament of the lamp sagged or changed its relationship to the lenses. It was necessary, also, to use a high amperage lamp, which was necessarily short-lived on account of the large current flow through the filament thereof. As the filament of the lamp gradually broke down or weakened due to the high current consumption, the position and the sound quality possessed by such person. For

these reasons, and perhaps others, it was difficult to secure and maintain a perfect reproduction of sound recordations carried by the film. All of the foregoing disadvantages and objectionable features of the prior devices have been overcome by means of the device of this invention, a detailed description of which follows.

Fig. l discloses a conventional motion picture projector, which includes a head I which includes the usual projecting lens structure 8 and means for moving the strip of motion picture film 9 past the projecting means. The film ordinarily is paid out from an upper reel l0, and passes between suitable guide rolls I2 onto a driving sprocket I3. The character [4 indicates an intermittently driven sprocket which performs to move the film through the film gate member I?) with a uniform jerky motion. The film passes from the intermittent sprocket 14 onto and over a smoothly rotating sprocket l6, whence the film is pulled past a suitable shield or film support I! by means of the smoothly rotating sprocket I8. From the sprocket I 8 the film is guided downwardly, as at I9, to a receiving reel (not shown). The device of the present invention is shown within the broken away area 20 of Fig. 1, wherein 2! indicates a conventional photo-electric cell having an anode 22 and a cathode 23. Light rays from an exciter lamp 24 encased within the device of the invention are projected from a barrel or tube 25 onto the film at a point of translation indicated at 26, and light, as modulated by the record markings on the film, passes through an opening 21 in the support member I? and plays upon the anode 22 of the photo 3. An apparatus for translating sound vibrations representative of speed, music and the like to or from a record carrier, which apparatus comprises a photo-electric cell, a low-voltage lowamperage exciter lamp of low intensity for said cell, prism means for condensing the rays from said lamp and for initially directing the condensed light in line formation, means adjacent to the carrier for finally determining the dimensions of the condensed light projection prior to passage thereof through the carrier and onto the photo-electric cell, means for varying the spacing between said last mentioned means and the prism means, an apertured plate for intercepting a pre-determined portion of the light rays directed toward the prism means by the lamp, and means for moving the record carrier relative to the projected line of light.

4. In an apparatus of the class described, the combination of a base, a frame supported by the base, a plurality of relatively adjusted longitudinal prisms supported by the frame in slightly spaced substantially parallel relationship, a barrel extended forwardly of and an apertured plate at the rear of the prisms, a source of light behind the aperture of the plate, the intensity of the light and the size of the aperture being coordinated to produce a desired projection and means associated with the barrel to limit egress of light rays condensed into line formation and projected into the barrel by said prisms.

5. In an apparatus of the class described, the combination of a base, a frame supported by the base, a plurality of longitudinal prisms supported by the frame in slightly spaced substantially parallel relationship, a barrel extended forwardly and an apertured plate extended rearwardly of the prisms, an exciter lamp behind the aperture of the plate, and means associated with the barrel to limit egress of light rays condensed into line formation and projected into the barrel by said prisms, the barrel, the plate aperture, the light source, and the slight space between the prisms being in alignment.

6. In an apparatus of the class described, the combination of a base, a frame supported by the base, a plurality of relatively adusted longitudinal prisms supported by the frame in slightly spaced substantially parallel relationship, a forwardly extended barrel at one side and an apertured plate at the opposite side of the prisms, a source of light behind the aperture of the plate, and means associated with the barrel to limit egress of light rays condensed into line formation and projected into the barrel by said prisms, the barrel, the plate aperture, the light source, and the slight space between the prisms being in alignment, and means for confining the direct rays of the light source to one face of the plate, its aperture, and so much of the prisms as is exposed through the aperture.

7. In an apparatus of the class described, the combination of a base, a frame supported by the base, a plurality of longitudinal flat-faced prisms supported by the frame, the faces of which extend in a common direction longitudinally of the prisms, adjustment means for rotatably supporting the prisms in spaced substantially parallel relationship to provide for varying the angular relationship of the faces of one prism to the faces of the other prism, a source of light behind the prisms, means for adjusting the prisms in unison relative to the source of light, a barrel disposed forwardly of the prisms transversely thereof, means for precluding forward projection of light rays otherwise than through the barrel, and means carried by the barrel for limiting the projection of light rays through the barrel.

8. In an apparatus of the class described, the combination of a base, a frame supported by the base, a plurality of longitudinal flat-faced prisms supported by the frame, the faces of which extend in a common direction longitudinally of the prisms, adjustment means for rotatably supporting the prisms in spaced substantially parallel relationship to provide for varying the angular relationship of the faces of one prism to the faces of the other prism, a source of light behind the prisms, means for adjusting the prisms in unison relative to the source of light, a barrel disposed forwardly of the prisms transversely thereof. means for precluding forward projection of light rays otherwise than through the barrel, and means carried by the barrel for limiting to a narrow fine line the projection of light rays through the barrel.

9. In an apparatus of the class described, the combination of a base, a frame supported by the base, a plurality of longitudinal fiat-faced prisms the faces of which extend in a common direction longitudinally of the prisms, means on the frame for supporting the prisms in closely spaced substantially parallel relationship with their faces disposed in proper relationship to project a condensed narrow line of light when light rays are directed onto the prisms, a source of light behind and adjacent to the prisms, an apertured plate intermediate the light source and the prisms for limiting application of light to the prisms over a restricted area, a barrel disposed forwardly of the prisms transversely thereof, means for precluding forward projection of light from the prisms otherwise than through the barrel, and means including a narrow slit in substantially the plane of the condensed narrow line of light, for limiting passage of the light rays through the barrel.

10. In an apparatus of the class described, the combination of a base, a frame supported by the base, a plurality of longitudinal flat-faced prisms the faces of which extend in a common direction longitudinally of the prisms, means on the frame for supporting the prisms in closely spaced substantially parallel relationship with their faces disposed in proper relationship to project a condensed narrow line of light when light rays are directed onto the prisms, a source of light behind and adjacent to the prisms, an apertured plate intermediate the light source and the prisms for limiting application of light to the prisms over a restricted area, a barrel disposed forwardly of the prisms transversely thereof, means for precluding forward projection of light from the prisms otherwise than through the barrel, means including a narrow slit in substantially the plane of the condensed narrow line of light, for limiting passage of the light rays through the barrel, and a photo-electric cell having light responsive means supported in the path of said condensed narrow line of light.

HENRY G. WEISS.

CERTIFICATE OF CORRECTION.

Patent No. 2,079,537. May 4, 1957.

HENRY G. WEISS.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, first column, line 2, claim 3, for "speed" read speech; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 29th day of June, A. D. 1937.

H r Va Ars al'e (Seal) Acting om%iss ioner of Patents 

